<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
    <title>title</title>
    <body id="" onload="">
        <input type="text" id="date" />
        <input type="button" value="加" id="Add" />
        <input type="button" value="减" id="Minus" />

        <script type="text/javascript">

            $ = function(o) { return typeof o === 'string' ? document.getElementById(o) : o };
            //设置当前日期
            var ma = [['1','3','5','7','8','10'],['4','6','9','11']];
            var dd = new Date();
            var x = dd.toLocaleString();
            var o = pasDate(x);
            $('date').value = o.join('-');
            console.log(o);

            //转化日期函数
            function pasDate(da) {
                var yp = da.indexOf('年'),
               mp = da.indexOf('月'),
               dp = da.indexOf('日');
                var y = da.substr(0,yp),
               m = da.substr(yp + 1,mp - yp - 1),
               d = da.substr(mp + 1,dp - mp - 1);
                return [y,m,d];
            }


            //判断数组a是否存在在元素n
            function check(n,a) {
                for(var i = 0,len = a.length;i < len;i++) {
                    if(a[i] == n) {
                        return true;
                    }
                }
                return false;
            }

            //闰?年?
            function isLeap(y) {
                return ((y % 4 == 0 && y % 100 != 0) || y % 400 == 0) ? true : false;
            }
            //实现加减f：'1'加，'0'减
            function trans(o,f) {
                var d = o.split('-');
                var l = isLeap(d[0]);

                if(f == '1') {
                    if((check(d[1],ma[0]) && (d[2] == '31')) || (check(d[1],ma[1]) && (d[2] == '30')) ||
                              (d[1] == '2' && d[2] == '28' && !l) || (d[1] == '2' && d[2] == '29' && l)) {
                        return d[0] + '-' + (d[1] * 1 + 1) + '-' + 1;
                    } else if(d[1] == '12' && d[2] == '31') {
                        return (d[0] * 1 + 1) + '-' + '1-1';
                    } else {
                        return d[0] + '-' + d[1] + '-' + (d[2] * 1 + 1);
                    }

                } else if(f == '0') {
                    if(check(d[1] - 1,ma[0]) && (d[2] == '1')) {
                        return d[0] + '-' + (d[1] - 1) + '-' + '31';
                    } else if(check(d[1] - 1,ma[1]) && (d[2] == '1')) {
                        return d[0] + '-' + (d[1] - 1) + '-' + '30';
                    } else if(d[1] == '1' && d[2] == '1') {
                        return (d[0] - 1) + '-' + '12-31';
                    } else if(d[1] == '3' && d[2] == '1' && !l) {
                        return d[0] + '-' + '2-28';
                    } else if(d[1] == '3' && d[2] == '1' && l) {
                        return d[0] + '-' + '2-29';
                    } else {
                        return d[0] + '-' + d[1] + '-' + (d[2] - 1);
                    }
                } else {
                    return;
                }

            }


            $('Add').onclick = function() {
                var v = $('date').value;
                $('date').value = trans(v,'1');
            }
            $('Minus').onclick = function() {
                var v = $('date').value;
                $('date').value = trans(v,'0');
            }        
  
        </script>

    </body>
</head>
</html>